"The more brutal the dictator, the harder to oust."
Unfortunately, true. Reflecting on the French Revolution, Alexis de Tocqueville observed that the "most dangerous moment for a bad government is when it begins to reform." What was correct in the 18th century is, sadly, still true in the 21st. It is probably not a coincidence that the list of authoritarians removed by street protest in recent years is largely populated by rulers whose regimes allowed at least a modicum of political opposition. Tyrants like Serbia's Slobodan Milosevic, Georgia's Eduard Shevardnadze, Kyrgyzstan's Kurmanbek Bakiyev, and Egypt's Hosni Mubarak may have been horrible in many ways, but their regimes were undoubtedly more permissive than those of many who have held onto power to this day.
If this is true, why do any dictators allow opposition in the first place? And why don't they simply go the full Tiananmen at the first sign of protest? Because running a truly ghastly dictatorship is tougher today than it used to be.
The interconnections of 21st-century civilization make it harder to control information and far more difficult and costly to isolate a country from the outside world than it was in the 20th. The death of communism, meanwhile, has robbed leftists and right-wing strongmen alike of a cover story for their anti-democratic practices. In the past decade, rulers of countries such as Uzbekistan and Yemen have used the West's newfound fear of militant Islam -- and the logistical necessities of the United States' post-9/11 wars -- to similar ends, but they number far fewer than the ideological tyrants who divvied up whole continents under Cold War pretexts a generation ago.
The result is that in more and more places, rulers are compelled to justify their practices by adding a touch of "democracy." Vladimir Putin chose to stand down -- though not far down -- in 2008 rather than break Russia's constitutional ban against a third consecutive presidential term, and even the Chinese Communist Party allows some competitive elections at the town and village levels. There are exceptions to this trend, of course: Turkmenistan, North Korea, and Burma spring to mind. But such regimes feel increasingly like remnants of the late, unlamented 20th century, rather than harbingers of things to come.